How do you know if someone is with you just for sex?

I have been dating someone sincs high school. Before that he was my best friend. I love him but that spark I felt when I was first with him, had faded. Our relationship was just a safe and easy one. About a month ago I met this guy, and it has helped me seen things I'm missing. For example I could talk for hours with this guy, where I had problems talking to my boyfriend. This guy is also hotter than my boyfriend. we also have EVERYTHING in common. And my boyfriend and I didn't share much in common, so we had nothing interesting to say or do. I felt like I have known this guy for a long time. Well I broke up with my boyfriend recently. Well ever since I broke up with him, it's like I have started to slowly stop liking this guy. Last night I was hanging out with him and my ex started calling a lot. The guy got very upset about my ex calling, very. And every time I am with him he is always so touchy, like I told him I wanted to start off as friends so I could build his trust but he never stops touching me. And every so often he gets very close to touching me inappropriately ans I point it out and he always acts like it was an accident. I ask him why he is so touchy-feely, and he said he doesn't know because he's never been that way before. He always tells me I'm beautiful and pretty too. He can't stop kissing me either. He acts like he had love at first sight too but I'm not sure if I can believe that anymore, like maybe it's just a show. He's also 7 years older than me (I'm 20 and still living with my mom while going to college). Should I trust him or is he just with me for sex?